>This isn't theoretical or a slippery slope argument; it's recent history. It's effective because it sounds "reasonable" on its face, but it's a ploy.

It quite literally is the slippery slope argument. You just don't want to call it that because the term is almost always used in the context of a fallacy, and you think you're right. It's like "freedom fighters" vs "terrorists". Nobody calls themselves terrorists, even terrorists.

Moreover the "It's effective because it sounds "reasonable" on its face, but it's a ploy" argument works equally well for any side, eg. it's not hard to imagine someone on the right saying "today it's Jan 6th protesters and that might seem reasonable, but tomorrow it's anyone at unite the right protests, and when president AOC's in power it's anyone who's protesting against trans surgery for minors".